Process of making leather flour from waste leather



Oct. 13, 1942. EMMITT 2,299,011

PROCESS OF MAKING LEATHER FLOUR FROM WASTE LEATHER Filed July 19, 1938grwenwbob RR.EITL m if? aux/114 6 I Patented Oct. 13, 1942 PROCESS OFMAKING LEATHER FLOUR FROM WASTE LEATHER Robert R. Emmitt, Will one-thirdto W. Cldc Harer, williai nspott,

iamsport, Pa", assignor of Application July 19, 1938, Serial No. 220,137

Claims.

This invention relates to a process of making counter-flow process witha solvent, as for example, ethylene dichloride, benzene, isopropylleather flour from waste leather and product therefrom and is animprovement over the process recited in an application filed by RobertR. Emmitt and Edward L. Schenck October 28, 1937, Serial Number 171,596,which became Patent No.

2,257,726 on October 7, 1941, covering a process of making from wasteleather fibrous material and product therefrom, the object of thisinvention being to provide a process by means of which the fibrousmaterial produced by the above referred to process can be converted intoa flour substance having inherent qualities. comparable with otherresinous molded plastics when molded under the combined action of heatand pressure.

Prior to my invention it has been impossible to grind waste leather intopowder having the characteristics of wood fiour and the like and I havefound that by compacting the pulp-like substance produced by the processas described in application Serial No. 171,596 with the pulp in a drystate, the pulp can be cut into granular form in the nature of powdersuch as wood flour and the like, which can be used to form articles andthe like by molding without the use of a binder.

I have found that by extensive experimenting that waste leather can beground by degreasing the same in order to form a fibrous material andthat this fibrous material can be compacted into a sheet which can befed slowly through rolls into a cutting machine where it is reduced insize by knife blade type of cutters running at high speed in order toobtain a shearing action of the knives so that the ends of the fibersare cut off in order to produce what I have termed flour.

Other and further objects and advantages of the invention will behereinafter set forth and the novel features thereof defined in theappended claims.

In carrying out my process of producing a leather flour from what I havetermed waste leather, such as scrap leather and the like, this wasteleather is disintegrated in an attrition mill of a special design so asto form a sponge-like material formed of sponge-like particles as thematerial is more or less shredded so that substantially the entiresurface of each particle will be exposed in order to allow thedegreasing solvent to thoroughly remove the oils and greases therefrom.

The material or substance thus formed, which is in the nature of asponge-like material is deposited in vats and agitated and treated in aether, naphth methyl Cellosolve, propylene dichloride andtrichlorethylene, so as to remove the grease, residue and the inherentoils present and while I am aware that many processes are now inexistence for degreasing material and recovering the solvent and theresidue from the solvent, I have found that a steam heating process issatisfactory to remove the solvents from the sponge-like substance andthat the solvents and oils can be recovered by distillation wherebythese by-products will have a commercial value.

With the above degreasing process, I have found that practically of theoils and greases are removed from the disintegrated leather.

The material with the solvent and oils removed is thoroughly dried,preferably by a passage of hot dry air through a rotary drum type ofdrier or other suitable types of continuous driers so as to reduce themoisture contents of the substance to the lowest practical minimum, forexample, about 6 of 1%.

The dry substance is then fed into a double plate attrition mill so asto grind the substance to reduce the size of the fibers thereof wherebya pulpy mass is formed which can be used for various purposes such as toform articles and the like. The above method produces a fibrous massfree from grease disclosed in the above referred to application, SerialNo. 171,596.

The pulpy mass of material in a dry state is then fed into a cuttingmill where it is reduced in size by the knife blade type of cuttersrunning at high speed which produces a shearing action so as to quicklycut off or bite off the ends of the previously formed fibers, whichreduces the mass into granular form in the nature of fiour, powder orthe like.

The flour thus formed contains substantially 5 or 10% glucose which actsas a binder and by wetting this flour in order to form a plastic mass,the same when subjected to the combined action of heat and pressure,such as a thermoplastic hydraulic press, forms a material which iscomparable with other resinous molded plastics having a sufficienttensile strength to stand the strain to which it is subjected.

The wetting of the material is preferably accomplished by spraying andagitating so as to produce a plastic mass of the desired consistency,but I do not wish to limit myself to any particular 5 method of wettingand agitating the mass as I have found that this substance can be placedin a vat, sprinkled and agitated and lust suillciently enough wateradded to form a plastic mass of the-desired consistency in order toallow it to be molded, pressed or rolled into the desired shape underthecombined action of heat and pressure or pressure only.

I have also found that a plastic mass having the desired consistency canbe produced by mixing the fiour with water and then drying 011 part ofthe water so as to produce a plastic mass of the desired consistencywhich can be readily molded under the combined action of heat into thedesired shape.

In the specification, the word flour is used to described a granularsubstance, such as powder, wood flour or pigment; degreasing is used todescribe the removal of substantially all grease, oil and residue;drying" is used to describe the removal of moisture therefrom: wettingis used to describe the conversion of the dry mass into a plastic massof the desired consistency; "molded is used broadly to define giving adesired shape to the plastic mass whether this is accomplished byrolling or pressing, with and without heat; cutting is used todifferentiate the powdering of the material by a cutting action ratherthan a grinding action; "fibrous material" is used broadly to describeda mass containing fibers; Waste leather" is used broadly to indicateleather having practically no commercial va'ue. I

m the drawing I have illustrated a flow sheet of one form of apparatusfor carrying out my invention. The small pieces of leather are fed tothe single plate attrition mill A where they are disintegrated. Thedisintegrated mass then passes to a receptacle B containing a solventwhere it is agitated for removing the grease therefrom. The degreasedparticles then pass through solvent extractors C, D and E. The particlesare then passed through indirect and direct driers F and G to removesubstantially all the moistur therefrom. These dried particles are thenfed into a double plate attrition mill H.

and are discharged therefrom as a soft felt-like mass of fibrousmaterial. This felt-like mass is fed into a compacting apparatus J. Thecompacted mass is then fed into a knife blade type of cutting machine Kand are discharged therefrom as flour. A solvent recovering device I isconnected to the apparatus as clearly shown.

From the foregoing description it will be seen that I have provided amethod of producing a leather flour which contains substantially 5 orglucose which enables the flour to be molded under the combined actionof heat and pressure into any desired shape so as to form articles ofvarious characters without the use of a binder of any kind, whicharticle will have a sufllcient tensile strength to allow the material tobe used for practically unlimited purposes, thereby utilizing a wasteproduct in the form of waste leather to form a leather flour from whichproducts can be formed.

What I claim is:

1, The process of making leather flour from waste leather which is firstmechanically disintegrating the leather, second degreasing thedisintegrated leather mass of material, third drying the mass ofdegreased material, fourth compacting the dried mass of material andfinally cutting the compacted mass into flour by a shearing action.

2. The process of making leather fiour from waste leather which consistsin first mechanically disintegrating the leather, second degreasing thedisintegrated leather by a solvent, third removing the solvent anddrying the mass, fourth compacting the resultant mass of material,finally cutting the compacted mass of material into.

flour by passing it through a knife blade type of cutting machine.

3. The process of making leather fiour from waste which consists infirst mechanically disintegrating the leather, second degreasing thedisintegrated leather by a solvent, third removing substantially all ofthe solvent from the degreased mass, fourth drying the mass, fifthreducing the size of the particles of the mass by grinding, sixthcompacting the resultant mass, finally passing the compacted massthrough a knife blade type of cutting machine to reduce the fibers toflour.

4. The process of making leather fiour from waste leather, whichconsists in first passing the scrap leather through a grinding machinefor mechanically disintegrating the same into small shredded particles,second agitating the mass thus formed in a vat containing a solvent forsubstantially removing all the grease therefrom including the inherentanimal oils, third removing substantially all of the solvent from thedegreased mass, fourth passing the mass through a drying apparatus toremove substantially all the moisture therefrom, fifth passing the driedmass through a grinding machine for reducing the size of the fibers to asoft felt-like mass of fibrous material, sixth compacting the felt-likemass of fibrous material and finally passing the compacted mass througha knife blade type of cutting machine for reducing the fibers to fiour.

5. The process of making leather fiour from waste leather, whichconsists in first passing the scrap leather through an attrition millfor mechanically disintegrating the mass into small shredded particles,second agitating the mass thus formed in a vat containing a solvent forsubstantially removing all the grease therefrom including the inherentanimal oils, third removing substantially all of the solvent from thedegreased mass, fourth passing the mass through a drying apparatus toremove substantially all the moisture therefrom, fifth passing the driedmass through a double plate attrition mill for reducing the size of thefibers to a soft felt-like mass of fibrous material, sixth compactingthe felt-like mass of fibrous material and finally passing the compactedmass through a knife blade type of cutting machine for reducing thefibers to flour.

ROBERT R. EMMTI.

